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Comment by philipkglass | Hacker News Reader

This is true only if you ignore costs. It falls apart as soon as you include market pricing or any other reasonable resource allocation mechanism.

It's like pretending that the liabilities represented by a huge coal ash pond are actually an asset, because if all the aluminum and silicon in the ash were purified and sold it would be worth a lot at present prices. The problem is that the cost of turning the waste into a salable product is higher than the market price. So it is still in fact a liability.

Under present and foreseeable economic and technical conditions, the asset-value of spent nuclear fuel does not exceed its liabilities.

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But the "spent" fuel is already a liability that no one has figured out how to get rid of.

Trying to permanently get rid of spent nuclear fuel under present and foreseeable conditions costs more than monitored dry cask storage for the indefinite future. A determination to permanently get rid of it despite the lower cost of once-through fuel cycles is a determination to take a modest liability and make it worse.

...unless you count the risks of something bad happening.

That’s always the unspoken actual debate when it comes to nuclear energy: what’s the probability of the worst case, and how does it affect the amortized cost?

We’re terrible at doing this calculation in other areas (e.g. terrorism vs. the cost of security theater), so it’s not especially informative to talk about the status quo. Clearly, we believe it’s cheaper to just store the stuff, or we wouldn’t be doing it. With nuclear energy, the exceptions matter a lot.

Both present once-through fuel cycles and "burner" reactor concepts produce fission products in proportion to energy generated. The short and medium lived fission products are the most intensely radioactive and dangerous byproduct of nuclear fission for the first few centuries of waste storage. The advantage of a burner reactor from a waste perspective is that it can consume longer lived actinide waste products like neptunium, plutonium, and americium. A burner reactor converts these actinide wastes into more intensely radioactive but less-long-lived fission products. (Additionally, some much longer lived and less intensely radioactive fission products like technetium 99 are also formed in burners and conventional reactors.)

This is to say that even if you place a high premium on avoiding environmental releases of radioactive materials, there is no appreciable benefit from burner reactors on a human time scale. The overall radiotoxicity inventory that needs ongoing management is nearly the same for both burners and once-through reactors for 200+ years after the fuel is done with. Further, fuel reprocessing facilities are themselves more likely to leak fission products into the environment than dry cask storage is.

> Further, fuel reprocessing facilities are themselves more likely to leak fission products into the environment than dry cask storage is.

But these fuel reprocessing already exist and the waste are currently already reprocessed to make MOX fuel, at least in some countries (France, UK, India, Russia and Japan).

Yes, and those plants release more becquerels of radioactive material into the environment when they reprocess fuel than would be released if the fuel elements were left intact in dry storage. I'm not saying that reprocessing plants release a dangerous amount of radioactive material. I'm saying that reprocessing makes things worse if your top priority is to prevent releases of radioactive materials into the environment. It also makes things worse if your top priority is to make nuclear-generated electricity affordable.

The first storage is actually opening in Finland. Its not that difficult to find a place technically. Its mostly a political problem.

I am often tempted to frame it as, "mostly an adulting problem".

"This is true only if you ignore costs. "

I think it would be better to say: "This is not true in many scenarios, depending on how costs are derived"

Liabilities are very hard to determine.

We are not yet to the point of operationalizing much of this stuff very well.

Given the vast amount of latent energy in such things, it's probably worthwhile looking at how we can effectively streamline and enable safety, fully accepting the fact may be 'it's impossible'.

Right, the liabilities are hard to determine and those liabilities may increase substantially if simply buried.

This is because most types of spent nuclear fuel slowly become "weapons-grade" as the short half-life isotopes decay.

The grade of plutonium is determined by the isotopic composition of the plutonium itself, not the short-lived fission products found around it in spent fuel. Weapons grade plutonium contains a high fraction of Pu-239 and a low fraction of Pu-240. The plutonium in spent fuel from commercial power reactors contains much more Pu-240 than weapons grade plutonium does.

Since Pu-240 has a shorter half life than Pu-239, it is technically true that the isotopic composition in spent fuel becomes more weapon-like as the fuel ages. But it is very slow because Pu-240 still has a half life in excess of 6500 years. It would take more than 13000 years for the decay of Pu-241 to improve the isotopic profile of today's power reactor plutonium to something near "weapons grade."

It's sunken cost. Anything you can do to extract value out of them offsets the cost of maintaining the SNF repos.

90% percent of uranium is not burnt, and it's fuel for MSR. Subtract the costs of movilizing the fuel, and tell me it's not worth dumping it in a MSR to be burtn almost to the 100%.

This would be a good argument if we already had industrial scale molten salt reactors just waiting to burn up spent fuel from light water reactors. But we don't, so anyone wishing to burn up spent fuel this way has to pay additional costs for researching and constructing the new reactors.

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